/*
 * Copyright (C) 2009, 2012, 2016 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include "include/JavaScriptCore/jit/ExecutableAllocator.h"
#include <wtf/DataLog.h>
#include <wtf/PrintStream.h>
#include <wtf/RefPtr.h>
#include <wtf/text/CString.h>

// ASSERT_VALID_CODE_POINTER checks that ptr is a non-null pointer, and that it is a valid
// instruction address on the platform (for example, check any alignment requirements).
#if CPU(ARM_THUMB2) && ENABLE(JIT)
// ARM instructions must be 16-bit aligned. Thumb2 code pointers to be loaded into
// into the processor are decorated with the bottom bit set, while traditional ARM has
// the lower bit clear. Since we don't know what kind of pointer, we check for both
// decorated and undecorated null.
#define ASSERT_VALID_CODE_POINTER(ptr) \
    ASSERT(reinterpret_cast<intptr_t>(ptr) & ~1)
#define ASSERT_VALID_CODE_OFFSET(offset) \
    ASSERT(!(offset & 1)) // Must be multiple of 2.
#else
#define ASSERT_VALID_CODE_POINTER(ptr) \
    ASSERT(ptr)
#define ASSERT_VALID_CODE_OFFSET(offset) // Anything goes!
#endif

namespace JSC {

    enum OpcodeID : unsigned;

// FunctionPtr:
//
// FunctionPtr should be used to wrap pointers to C/C++ functions in JSC
// (particularly, the stub functions).
    class FunctionPtr {
    public:
        FunctionPtr()
                : m_value(0) {
        }

        template<typename returnType>
        FunctionPtr(returnType(*value)())
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1>
        FunctionPtr(returnType(*value)(argType1))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2>
        FunctionPtr(returnType(*value)(argType1, argType2))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3>
        FunctionPtr(returnType(*value)(argType1, argType2, argType3))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3, typename argType4>
        FunctionPtr(returnType(*value)(argType1, argType2, argType3, argType4))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3, typename argType4, typename argType5>
        FunctionPtr(returnType(*value)(argType1, argType2, argType3, argType4, argType5))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3, typename argType4, typename argType5, typename argType6>
        FunctionPtr(returnType(*value)(argType1, argType2, argType3, argType4, argType5, argType6))
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }
// MSVC doesn't seem to treat functions with different calling conventions as
// different types; these methods already defined for fastcall, below.
#if CALLING_CONVENTION_IS_STDCALL && !OS(WINDOWS)

        template<typename returnType>
        FunctionPtr(returnType (CDECL *value)())
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1>
        FunctionPtr(returnType (CDECL *value)(argType1))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2>
        FunctionPtr(returnType (CDECL *value)(argType1, argType2))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3>
        FunctionPtr(returnType (CDECL *value)(argType1, argType2, argType3))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3, typename argType4>
        FunctionPtr(returnType (CDECL *value)(argType1, argType2, argType3, argType4))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }
#endif

#if COMPILER_SUPPORTS(FASTCALL_CALLING_CONVENTION)

        template<typename returnType>
        FunctionPtr(returnType (FASTCALL *value)())
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1>
        FunctionPtr(returnType (FASTCALL *value)(argType1))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2>
        FunctionPtr(returnType (FASTCALL *value)(argType1, argType2))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3>
        FunctionPtr(returnType (FASTCALL *value)(argType1, argType2, argType3))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        template<typename returnType, typename argType1, typename argType2, typename argType3, typename argType4>
        FunctionPtr(returnType (FASTCALL *value)(argType1, argType2, argType3, argType4))
            : m_value((void*)value)
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }
#endif

        template<typename FunctionType>
        explicit FunctionPtr(FunctionType *value)
        // Using a C-ctyle cast here to avoid compiler error on RVTC:
        // Error:  #694: reinterpret_cast cannot cast away const or other type qualifiers
        // (I guess on RVTC function pointers have a different constness to GCC/MSVC?)
                : m_value((void *) value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        void *value() const { return m_value; }

        void *executableAddress() const { return m_value; }


    private:
        void *m_value;
    };

// ReturnAddressPtr:
//
// ReturnAddressPtr should be used to wrap return addresses generated by processor
// 'call' instructions exectued in JIT code.  We use return addresses to look up
// exception and optimization information, and to repatch the call instruction
// that is the source of the return address.
    class ReturnAddressPtr {
    public:
        ReturnAddressPtr()
                : m_value(0) {
        }

        explicit ReturnAddressPtr(void *value)
                : m_value(value) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        explicit ReturnAddressPtr(FunctionPtr function)
                : m_value(function.value()) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        void *value() const { return m_value; }

        void dump(PrintStream &out) const {
            out.print(RawPointer(m_value));
        }

    private:
        void *m_value;
    };

// MacroAssemblerCodePtr:
//
// MacroAssemblerCodePtr should be used to wrap pointers to JIT generated code.
    class MacroAssemblerCodePtr {
    public:
        MacroAssemblerCodePtr()
                : m_value(0) {
        }

        explicit MacroAssemblerCodePtr(void *value)
#if CPU(ARM_THUMB2)
        // Decorate the pointer as a thumb code pointer.
        : m_value(reinterpret_cast<char*>(value) + 1)
#else
                : m_value(value)
#endif
        {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        static MacroAssemblerCodePtr createFromExecutableAddress(void *value) {
            ASSERT_VALID_CODE_POINTER(value);
            MacroAssemblerCodePtr result;
            result.m_value = value;
            return result;
        }

        static MacroAssemblerCodePtr createLLIntCodePtr(OpcodeID codeId);

        explicit MacroAssemblerCodePtr(ReturnAddressPtr ra)
                : m_value(ra.value()) {
            ASSERT_VALID_CODE_POINTER(m_value);
        }

        void *executableAddress() const { return m_value; }

#if CPU(ARM_THUMB2)
        // To use this pointer as a data address remove the decoration.
        void* dataLocation() const { ASSERT_VALID_CODE_POINTER(m_value); return reinterpret_cast<char*>(m_value) - 1; }
#else

        void *dataLocation() const {
            ASSERT_VALID_CODE_POINTER(m_value);
            return m_value;
        }

#endif

        explicit operator bool() const { return m_value; }

        bool operator==(const MacroAssemblerCodePtr &other) const {
            return m_value == other.m_value;
        }

        void dumpWithName(const char *name, PrintStream &out) const;

        void dump(PrintStream &out) const;

        enum EmptyValueTag {
            EmptyValue
        };
        enum DeletedValueTag {
            DeletedValue
        };

        MacroAssemblerCodePtr(EmptyValueTag)
                : m_value(emptyValue()) {
        }

        MacroAssemblerCodePtr(DeletedValueTag)
                : m_value(deletedValue()) {
        }

        bool isEmptyValue() const { return m_value == emptyValue(); }

        bool isDeletedValue() const { return m_value == deletedValue(); }

        unsigned hash() const { return PtrHash<void *>::hash(m_value); }

    private:
        static void *emptyValue() { return bitwise_cast<void *>(static_cast<intptr_t>(1)); }

        static void *deletedValue() { return bitwise_cast<void *>(static_cast<intptr_t>(2)); }

        void *m_value;
    };

    struct MacroAssemblerCodePtrHash {
        static unsigned hash(const MacroAssemblerCodePtr &ptr) { return ptr.hash(); }

        static bool equal(const MacroAssemblerCodePtr &a, const MacroAssemblerCodePtr &b) {
            return a == b;
        }

        static const bool safeToCompareToEmptyOrDeleted = true;
    };

// MacroAssemblerCodeRef:
//
// A reference to a section of JIT generated code.  A CodeRef consists of a
// pointer to the code, and a ref pointer to the pool from within which it
// was allocated.
    class MacroAssemblerCodeRef {
    private:
        // This is private because it's dangerous enough that we want uses of it
        // to be easy to find - hence the static create method below.
        explicit MacroAssemblerCodeRef(MacroAssemblerCodePtr codePtr)
                : m_codePtr(codePtr) {
            ASSERT(m_codePtr);
        }

    public:
        MacroAssemblerCodeRef() {
        }

        MacroAssemblerCodeRef(Ref<ExecutableMemoryHandle> &&executableMemory)
                : m_codePtr(executableMemory->start()), m_executableMemory(WTFMove(executableMemory)) {
            ASSERT(m_executableMemory->isManaged());
            ASSERT(m_executableMemory->start());
            ASSERT(m_codePtr);
        }

        // Use this only when you know that the codePtr refers to code that is
        // already being kept alive through some other means. Typically this means
        // that codePtr is immortal.
        static MacroAssemblerCodeRef createSelfManagedCodeRef(MacroAssemblerCodePtr codePtr) {
            return MacroAssemblerCodeRef(codePtr);
        }

        // Helper for creating self-managed code refs from LLInt.
        static MacroAssemblerCodeRef createLLIntCodeRef(OpcodeID codeId);

        ExecutableMemoryHandle *executableMemory() const {
            return m_executableMemory.get();
        }

        MacroAssemblerCodePtr code() const {
            return m_codePtr;
        }

        size_t size() const {
            if (!m_executableMemory)
                return 0;
            return m_executableMemory->sizeInBytes();
        }

        bool tryToDisassemble(PrintStream &out, const char *prefix = "") const;

        bool tryToDisassemble(const char *prefix = "") const;

        JS_EXPORT_PRIVATE CString disassembly() const;

        explicit operator bool() const { return !!m_codePtr; }

        void dump(PrintStream &out) const;

    private:
        MacroAssemblerCodePtr m_codePtr;
        RefPtr<ExecutableMemoryHandle> m_executableMemory;
    };

} // namespace JSC

namespace WTF {

    template<typename T>
    struct DefaultHash;
    template<>
    struct DefaultHash<JSC::MacroAssemblerCodePtr> {
        typedef JSC::MacroAssemblerCodePtrHash Hash;
    };

    template<typename T>
    struct HashTraits;
    template<>
    struct HashTraits<JSC::MacroAssemblerCodePtr> : public CustomHashTraits<JSC::MacroAssemblerCodePtr> {
    };

} // namespace WTF
